Long time no post!

I have a small question regarding drop tunings. My band are tuning down to G (please don't bother starting a debate over drop tunings, it's been done to death) and I'm using an Active Deluxe P bass. I've strung it with a low B and set it up. My question is, is there absolutely anything else that I can do to help increase the tension, apart from getting a 35" scale bass/5 string/etc?

The construction of the string (the core and the materials) can impact on tension, so it might be worth looking for a set of strings designed for higher tension. Alternatively you could just get heavier gauge strings on there.